This invention relates to a collapsible energy-absorbing support system for a vehicle steering mechanism.
Mechanisms have been devised for allowing vehicle steering wheels to collapse in the event that the driver of the vehicle should forcibly impact the steering wheel during a vehicle crash incident e.g. a front end collision. Such mechanisms are conventionally formed out of stamped metal components suitably welded, or otherwise connected together, to form a deformable support system for the steering shaft and steering wheel.
One problem with such conventional mechanisms is that the stamped components can deflect, or deform, under normal operating loads. In a crash situation the mechanisms can act as a stiff spring so as to delay or prevent collapse of the steering wheel, with the possibility of a momentary oscillating condition tending to prolong human injury. Conventional collapse systems are somewhat unpredictable in crash situations.
The present invention relates to an energy-absorbing support system for a vehicle steering mechanism, wherein a principal component of the support system is a one-piece rigid metal die casting. In a crash situation, the connection between the die casting and an overhead mounting bracket shears at a predictable shock loading, with minimal time delay in the collapse action. The rigidness of the metal die casting increases the predictability of the response to shock loading. (e.g. during a front-end collision).
In preferred practice of the invention the energy-absorbing support system includes a tubular shaft housing rigidly joined to the lower end of the aforementioned die casting. The tubular shaft housing extends downwardly into a tubular casing carried by a lower mounting bracket. An annular friction ring within the tubular casing exerts a strong frictional force on the outer surface of the tubular shaft housing, so that after release of the die casting from the overhead mounting bracket the shaft support assembly is brought to a controlled stop, without undesired rebound. The friction ring rigidly supports the tubular shaft housing during normal vehicle operation, thereby precluding any undesired vibratory motion of the shaft support system.
Further features of the invention will be apparent from the attached drawings and description of an illustrative embodiment of the invention.